Inertia type brake control apparatus



J. c. MCCUNE 2,208,768

INERTIA TYPE BRAKE CONTROL APPARATUS July 23, 1940.

Filed Dec. 51, 1958 3 Sheets-Sheet 1 Synchronizing Train Wire Volume Reservoir 74 Release MagVoIve 68 Adjusling Pelu'y 'l l l l 50 Supply Eeservolr Supply 7 l6 eservo'sr' Direclion Coordi nolor 92 Main 269 Reservoir 28B 256 244!) 296 Brake Broke Cylmder 5 285 Cylinder TEUCK No.1 142 Brake Valve INVENTOR HI- TW f JOSEPH C. McCUNE To oppos' re E 1 o opposi 6 BY wheel g wheel 9 W ATTORNEY July 23, 1940. Y J. C. MOCUNE 2,208,768

INERTIA TYPE BRAKE CONTROL APPARATUS Filed Dec. 31, 1939 s Sheets-Sheet 2 Synchronizing Train Wire Adjusfing Eeloy PP v Reservoir Direcfion Coordinaior Brake Cylinder TRUCK NO. 2

Y 2 2 INVENTOR v Z T JOSEPH CMCCUNE To oppos'fie L i o opposl a By wheel g Wheel 9W ATTORNEY July 23, 1940. J, c. McCUNE 2,208,768

INERTIA TYPE BRAKE CONTROL APPARATUS Filed Dec. 31, 1939 3 Sheets-Sheet 3 INVENTOR JOSEPH C. MCCUNE mq9 m ATTORNEY Patented July 23, 1940 UNITED STATES PATENT ()FFICE INERTIA TYPE BRAKE CONTROL APPARATUS Joseph C. McCune, Edgewood, Pa., assignor to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application December 31, 1938, Serial No. 248,654:

19 Claims. (01. 303-21) This invention relates to inertia type brake the slipping of the wheel and accelerate back control apparatus for vehicles such as railway toward a speed corresponding to car or train cars or trains, and particularly to brake control speed even if in some cases the wheels might acapparatus including rotary inertia devices assotually momentarily attain the sliding state. ciated with the wheels or wheel-axles of a car or There is, however, no assurance that the vehicle train and operatively responsive to the rate of wheels will accelerate back toward a speed corchange of rotative speed of the associated car responding to vehicle speed if the degree of apwheel or axle for regulating and controlling the plication remaining after the automatic reducbrakes on the wheel or axle. tion effected in response to initial slipping of the In my prior Patent 2,132,959, assigned to the wheels is sufficient to hold the wheels in locked 10 assignee of this application, there is disclosed a condition, for then the wheels will continue to brake control equipment for railway cars and slide due to the application of the brakes at the trains including a rotary inertia device associated reduced degree.

with each wheel axle. This equipment is effec- It is accordingly an object of my invention to tive to automatically regulate the degree of a provide a brake control system, similar in char- 15 brake application so as to effect a substantially acter to that disclosed in my above-mentioned uniform rate of retardation of the train, and is patent, and including an arrangement for insuralso operative automatically upon the slipping of ing the complete release of the brakes on a the individual wheel-axles to rapidly release the slipping wheel so that, even if the wheel does brakes on the slipping. wheels to prevent sliding slide, the sliding will be only momentary. 20 thereof and then reapply the brakes in response More specifically it is an object of my invention to acceleration of the slipping wheels back toward to initiate the release of the brakes on a slipping a speed corresponding to vehicle speed and to a wheel and continue to reduce the degree of apdegree determined by the length of time the slipplication on the slipping wheel until such time :15 ping wheels accelerate in excess of a certain as the wheel rotatively accelerates at a rate in rate. excess of a certain rate while returning back to- In my above-mentioned patent, fluid under ward a speed corresponding to car speed, thus pressure is automatically released from the brake insuring the complete release of the brakes on a cylinder applying the brakes on slipping wheels slipping wheel if it should happen to slide.

M) only so long as the rate of rotative deceleration My prior Patent 2,173,946, and assigned to I of the slipping wheels exceeds a certain rate, the the assignee of this application, discloses and release of fluid under pressure from the brake broadly claims a brake control equipment, incylinder or cylinders being terminated when the eluding a rotary inertia device, operating in a rate of rotative deceleration of the slipping manner to insure release of the brakes on a slipwheels falls below a certain rate in response to ping wheel and thus prevent more than momenthe release of the brakes. If the retarding or tary sliding of the wheel. It should be underbraking force on the slipping wheel is relieved instood, therefore, that the claims of the present stantly and rapidly upon the initiation of slipapplication do not definethis release insuring ping of the wheels, then a sufiicient degree of refeature in its broadest scope.

44) duction in the retarding force will be effected to Another object of my invention is to provide a cause the slipping wheels to begin to accelerate control valve mechanism of novel construction toward a speed corresponding to vehicle speed for effecting the rapid release of fluid under preswithout actually reducing to a locked or nonsure from the brake cylinders when a wheel rotative state, that is sliding. As employed hereslips as well as an arrangement including the 45 in, the term slipping refers to the rotation of control valve mechanism for insuring the rapid 5 a vehicle wheel at a speed less than that correresupply of fluid under pressure to the brake spending to vehicle speed as distinguished from cylinder when the rate of acceleration of a slipthe term sliding which refers to the dragging ping wheel back toward car speed exceeds a cerof a vehicle wheel along a road surface or rail in tain rate.

9 a locked or non-rotative state. In my above-mentioned Patent 2,132,959, a

It is expected that, in the operation of the rotary inertia device is provided which includes apparatus disclosed in my above-mentioned pata rotary inertia element in the form of a flyent, the vehicle wheels will ordinarily respond to wheel that shifts forwardly and backwardly out the automatic reduction in the degree of the apof a certain neutral position with respect to a plication of the brakes following in response to shaft rotated according to the speed of rotation 55 of a vehicle wheel-axle in response to deceleration and acceleration respectively of the wheelaxle. The. fly-wheel carries a brush element which is adapted to engage in succession a plurality of contact segments carried by the rotating shaft driven from the axle when it shifts forwardly and .backwardly out of its normal position with respect to the shaft. The control system is such as to require an individual collector ring for each of the contact segments carried.

on the shaft in order to provide a continuous electrical connection thereto while the shaft is rotating.

It is an object of my present invention to provide a rotary inertia device of novel construction adapted to be associated. with an individually mounted wheel, as distinguished from a wheelaxle, and associatively connected in a control system in such manner as to effect a substantial reduction in the number, of collector rings required by the rotary inertia device.

It is a further object of my invention to provide a brake control equipment including rotary inertia devices of the character just referred to and a novel direction coordinator, adapted so that an identical operation is effected automatically under the control of the rotary inertia devices, either during the normal regulation of the retardation rate or during a slipping cycle, whether the vehicle Wheels are rotating in one direction or in the opposite direction.

A further object of my invention is to provide a brake control equipment for a car or train including means for preventing undesired or erratic operation of the brakes under the control of the rotary inertia-devices when subject to shocks and jars which cause momentary unintended operation of the rotary inertia devices.

The above objects, and other objects of my invention which will be made apparent hereinafter, are attained by means of an illustrative embodiment of my invention subsequently to be described and, shown in the accompanying drawings wherein- Figs. 1 and 2, taken together, represent in diagrammatic form a brake control equipment embodying my invention,

Fig. 3 is a fragmentary vertical sectional view of a car wheel and a rotary inertia device asso ciated therewith, and

Fig. 4 is a sectional view taken on the line ll of Fig. 3 showing in further detail the construc tion of the rotary inertia device.

BRIEF DESCRIPTION or EQUIPMENT Referring to Figs. 1 and 2 taken together, the equipment shown is that for a single car having two wheel trucks designated respectively as No. 1 and No. 2, each of which trucks comprises four wheels, only the two wheelson one side of each truck being shown for simplicity. It should be understood, moreover, that in the adaptation of the brake control equipment to a train of cars, the equipment on each of the cars substantially duplicate that shown in Figs. 1 and 2, the various train wires and train pipes, subsequently to be described, extending in the usual manner throughout all the cars of the train. Is should be understood also that the brake control equipment is not limited to conventional cars but may also be applied in any obvious manner to cars of the articulated type wherein a single wheel truck supports the adjacent ends of two cars.

For illustrative purposes, the brake equipment is shown as including a brake cylinder H for each pair of wheels, effective to apply the brake shoes (not shown) associated with the tread or other braking surface on the car wheels upon the supply of fluid under pressure to the brake cylinders and to release the shoes upon the release of fluid under pressure from the brake cylinders. However, it should be understoodthat any type of brake means, such as a drum or disc type of brake means may be employed.

The brake control equipment embodying the features of my invention may be adapted to operate in connection with any type of brake apparatus whereby the supply of fluid under pressure to the brake cylinders and the release therefrom may be eflected under manual control. For illustrative purposes, there is shown in Figs.

1 and 2 a so-called straight-air brake system ineluding a straight-air pipe l2 extending from car to car throughout the train and to which fluid under pressure is supplied from a main reservoir it on one of the cars, such as the control car, under the control of a manually operated selflapping brake valve It. The pressure established in the straight-air pipe i2 is effective to operate a so-called adjusting relay l5, one of which is provided for each wheel truck for a purpose which will be made apparent hereinafter, the relay it being effective in turn to supply fluid under pressure from 'a supply reservoir 16, one of which is provided for each car, to the brake cylinders l l of the associated wheel truck.

The supply reservoir Hi on each car is charged with fluid under pressure from the main reservoir 53 as from a so-called reservoir pipe I! extending from car to car throughout the train.

Associatively connected in the supply communication to the adjusting relays I5 is a volume reservoir It which provides the necessary volume to insure stabilized control of the fluid pressure operating the adjusting relays IS.

The operating fluid pressure for the adjusting relays i5 is under the control of a so-called cutofl" magnet valve I 9 and a release magnet valve 2! which are in turn controlled electrically by the rotary inertia devices 22 associated individually with each wheel and hereinafter to be described in detail.

Interposed in the supply communication from each of the adjusting relays l5 to the brake cylinders H for the corresponding wheel truck is a so-called slip magnet valve 23 and associated therewith a so-called reapplication magnet valve 24.

The slip magnet valve 23 is operated under the control of the rotary inertia devices 22 of the corresponding wheel truck, when any one of the four wheels of the truck begins to slip, to cut off the supply of fluid under pressure from the supply reservoir Iii to the brake cylinders H of that truck and rapidly release fluid under pressure therefrom.

The reapplication magnet valve 24 is operatively controlled by the rotary inertia devices 22 of the corresponding Wheel truck to resupply fluid under pressure from local supply reservoirs '25 to the brake cylinders I l under the control of .the rotary inertia devices 22 when the slipping through the medium of a so-called synchronizing train wire 34 which extends from car to car throughout the train, each car being provided with electromagnetic switches or relays 35 and 36.

The relay 35 is under the control of the rotary inertia devices 22 associated with any of the wheels of either of the Wheel trucks No. l and No. 2 of a car to eifect energization of the synchronizing train wire. The relay 36 is connected to and operated on the energization of the synchronizing train wire 36 to effect operation of the release magnet valve 2|.

A so-called direction coordinator 2B is provided for each wheel truck including a plurality of electromagnetic switches or relays 21, 23 and 25 for causing the rotary inertia devices 22 to eifect operation of the slip magnet valve and reapplication magnet valve 24 in sequence whether the car wheels are rotating in one direction or the opposite direction upon application of the brakes resulting in slipping of the wheels.

A suitable source of electric current for operating the equipment is provided, illustrated in the form of two batteries 30 and 3!. Associated with battery 3| is a pressure operated switch device 32 for preventing the supply of current from the battery unless the pressure established in the volume reservoir l8 and effective to operate the adjusting relays i5 exceeds a certain low pressure such as five pounds per square inch.

In addition a choke or inductance coil 53 is provided in the electrical circuits in such manner as to prevent undesired and erratic operation of the brakes under the control of the rotary inertia devices when the rotary inertia devices are momentarily and undesirably actuated in response to impact or shock to the cars, as during switching operations.

DETAILED Drrsonrrrrow or EQUIPMENT Each of the various above-mentioned parts of the equipment will now be considered in detail and the cooperative relation thereof with other parts of the equipment described in order to obtain a comprehensive understanding of the equipment.

The self-lapping manually operated brake valve I 4 is illustrated in outline form only for the reason that the construction and operation thereof is shown and described in detail and claimed in Patent 2,042,112 of Ewing K. Lynn and Rankin J. Bush. Since reference may be had to the above-mentioned patent it is deemed necessary, for purposes of the present application, to explain the operation of the brake valve device M only functionally. With the operating handle 4! of the brake valve 14 in its normal position, fluid under pressure in the straight-air pipe I2 is vented to atmosphere at the brake valve device l4 and thus the straight-air pipe I2 is normally at atmospheric pressure. When the brake valve handle 4! is shifted in a horizontal plane out of its normal position in a socalled service zone, fluid under pressure is supplied from the main reservoir i3 to straight-air pipe 12 and the brake valve is automatically effective to establish a pressure in the pipe 12 which corresponds sub: stantially to the degree of displacement of the brake valve handle 4! out of its normal release position. When the brake valve handle is shifted further into a so-called emergency position, maximum pressure corresponding to main reservoir pressure is established in the straight-air pipe [2. The brake valve M has a pressure-maintaining operation and thus if the pressure in the straightair pipe l2 tends to diminish due to leakage, the brake valve device 14 automatically functions to maintain the pressure corresponding to the position of the brake valve handle 4|.

The adjusting relay l5 may be of any suitable construction whereby it may be manually set or adjusted according to the weight or load, calculated or measured, carried by a particular wheel truck corresponding thereto, so as to automatically and correspondingly proportion the pressure of the fluid established in the brake cylinders of the associated wheel truck to different degrees, in response to and with respect to any given operating pressure. The adjusting relays l5 are not a part of my present invention and accordingly it is deemed unnecessary to show the construction thereof and describe them in detail. It should be understood that the adjusting relays [5 are not automatically sensitive to variations in the load carried by a wheel truck. The adjusting relays I5 are merely set initially by hand upon the installation of the equipment and thereafter no adjustment is made except as effected manually. The purpose of the adjusting relays I5 is to provide some means whereby to establish in the brake cylinders of wheel trucks carrying different loads, different pressures varying in some measure according to the load on the truck, in

response to a selected degree of application of.

the brakes set up under manual control.

The cut-off magnet valve l9 comprises a casing having a chamber 44 containing a ball valve 45 and a bore 46 containing a valve piston 41. Interpos'ed between the casing and the back side of the valve piston 41 within the bore 46 is a coil spring 48 that normally yieldingly urges the valve piston 4'! upwardly into seated relation on an annular rib seat 49 which surrounds the opening of a passage 5| connecting the chamber 44 to the bore 46. The valve piston 41 is provided with a stem 52 which projects through the passage 5| into the chamber 44 and which is of such length as to unseat the ball valve 45 from a cooperating valve seat, formed on the casing at the end of passage 5| opposite to the annular rib seat 49. when the valve piston 41 is seated on the annular rib seat 49.

The chamber 44 is constantly connected to the straight-air pipe I?! through a branch pipe 53 and the passage 5! is connected by a branch passage 54 and pipes 55 and 55 to the volume reservoir IS.

The cut-off magnet valve further comprises an electromagnetically operated valve having a double beat valve 5'! and an electromagnet winding 58 associated with a plunger-like stem 59 of the double beat valve. The double beat valve 51 is contained in a chamber 6!, formed in the casing of the cut-off magnet valve [9, which is in open communication with the bore 45 at the back of the valve piston .7. With the electromagnet winding 58 deenergized, the double beat valve 57 is urged upwardly to an upper seated position by a coil spring 82 and communication is established past the lower seat of the double beat valve 57 between the chamber 61 and a chamber 63 to which the pipe 55 is connected through a passage 55. It will accordingly be seen that when fluid under pressure is supplied through pipe 53 to the volume reservoir it, the pressure of the fluid acts on the back side of the valve piston All and, aided by the spring 43, prevents downward movement of the valve piston 31'. Accordingly the ball valve 45 is maintained unseated to maintain open the communication through which fluid under pressure may be supplied from the pipe 53 to the volume reservoir 18.

When the electromagnet winding 58 is energized, the double beat valve Si is actuated to its lower seated position wherein thesupply communication to the back side of the valve piston t! is closed and communication is established past the upper valve seat 'of the valve 51 through an exhaust port t l opening out of the chamber 6! so that fluid under pressure is vented from the back side of valve piston 61. The pressure of the fluid supplied through the pipe 53 and active in the passage on the valve piston t l is thus efiective to overcome the spring it and shift the valve piston downwardly so that the stem 52 of the valve piston 47 is withdrawn from supporting relation under the ball vaive it which then drops into seated relation on its associated valve seat to close communication'from the chamber t l to the passage 5!.

It will thus be seen that as long as the electromagnet winding 58 of the cut-oil magnet valve i9 is deenergized, fluid under pressure may be supplied through the pipe 53 to the volume reservoir i8 and that when the electromagnet vinding 53 is energized, the supply communication to the volume reservoir is closed.

The release magnet valve 2i comprises a casing having a bore 65 in which a valve piston 58 operates. Valve piston so is normally urged downwardly into seated relation on an annular rib seat 5'? by a coil spring interposed between the back side of the valve piston and an annular flange 59 formed in the casing and projecting into the bore 65. Pipe 55 leading from the cutoff magnet valve 59 is connected into the space at the outer seated area of the valve piston to and an exhaust port 5% of a certain so ected flow area opens out of the inner area of the valve piston within the annular rib seat The valve piston 88 is provided with a restricted port 12 therein through which fluid under pressure may flow to the back side of the valve piston 65 within the bore 65.

The release magnet valve 23 further comprises an electroniagnetically operated valve" having a valve it of the poppet type provided with a plunger like stem which projects through an exhaust port it in the wall of the casing and has associated therewith an electromagnet winding ll. The valve is is contained in an extension of the bore and is normally urged into seated relation on an associated valve seat formed on the casing by a coil spring '58 interposed between the valve and the side of the annular flange 59 opposite to that engaged by the spring 68.

' With the electromagnet winding 'i'i of the release magnet valve Ei ole-energized, the valve Ed is maintained in seated position and thus when fluid under pressure is supplied through the pipes 55 and 56 to the volume reservoir ii the fluid under pressure which flows through the restricted port 12 in the valve piston 65 to the back side thereof, assisted by the spring it, maintains the valve piston 55 in seated relation on the annular rib seat 67. When the magnet winding E? of the release magnet valve 211 is energized, the valve 1 2 is unseated and the space within the bore 65 at the back side of the valve piston 66 is vented to atmosphere through the exhaust port it. In such case, the pressure of fluid acting on the outer seated area of the valve piston 66 overcomes the s ring 5 3 and shifts the valve piston upwardly, thereby unseating it from the annular rib seat El. With the valve piston fit unseated, fluid under pressure is accordin ly vented from the pipe 55 and. connected volume reservoir l8 through the exhaust port ii, at arate determined by the size of the port which is selected on a basis hereinafter explained. The port 12 in the valve piston 6% permits only a restricted flow of fluid under pressure to the back side of the valve piston 55, and thus once the valve piston G6 is unseated upwardly it is maintained unseated as long as the magnet winding 'i'l is energized and tie valve i l unseated. When magnet winding H is deenergized and valve l4 resea-ted, the chamber formed at the back side of valve piston 66 within bore 65 is promptly charged with fluid under pressure through port 32 and the spring 68 thus promptly reseats the valve piston.

As previously explained, each of'the'wheel trucks No. 1 and 'No. 2 is provided with a slip magnet valve 23 and a reapplication magnet valve 26. The slip magnet valves and reapplication magnet valves for the two Wheel-trucks are identical in construction and operation and accordingly only those for truck No. l are shown in detail and described herein.

The slip magnet valve 23 comprises a casing in which are contained a one-way'or check valve device in the form of a ball valve 8!, a valve piston 82, a release valve in the form of a valve piston "53, and a double beat valve 3% operated by an electromagnet winding 85 for controlling 'the operation of the valve pistons '82 and 83.

The ball valve 3! is contained in a chamber 86 which is constantly connected to the brake cylinder supply pipe 87 leading out'of the corresponding relay 55. The ball valve 3-5 is normally held unseatcd bythe upwardly projecting stem 88 of the valve piston 82 which is normally maintained in an upper seated position on an annular rib seat 8E by a coil spring 9! interposed between the casing and the back side or. the valve piston 82. valve piston closes a port m in thecaslng connecting the bore, in which the valve piston 82 operates, to a chamber 93. The stem 88 {on valve piston 82 extends through port 39o, chamber 93 and a passage 92 connecting the-chamber 93 to chamber 88. Chamber 93 is in constant communication through apassage and .pipe 9d, and a branch pipe 95 with the two brakecylinders ll of the associated wheel truck.' ,Acc'ordingly, with the ball valve 8! unseated, fluid under pressure may be supplied fromthe supply reservoir it to the brake cylinders H in response to the operation of the corresponding relay I5. I

A switch device operated by movementof the stem 88 of valve piston'82 is provided inchamber 93 and comprises a contact member 98, carried in insulated relation on the stem 88, and a pair of associated contact members 99a, carried in spaced insulated relation on the casing. The contact members 96a are so positioned as to be simultaneously engaged by contact member 90 only when the valve piston 82 is in its upper seated position. The purpose of this switch device will be made apparent hereinafter.

The release valve piston 83 operates in a suitable bore in the casing and is normally urge-d In its upper seatedposition or All The double beat valve 84 is' contained in a chamber IDI which is connected by a passage I02'to the chamber at the back side of the valve piston 82 and a branch passage I 03 of passage I02 to the chamber at the backside of the valve piston 83. hits upper seated position to which it is urged by a'coil spring I04 the double beat valve 84 closes an exhaust port IDES opening out of chamber IDI and simultaneously establishes communication past the low-er seat thereof from chamber IllI to a branch passage I 05 of the brake cylinder supply passage 94. Thus with the double beat valve 84 in its upper seated position, fluid under pressure supplied into the brake cylinder passage and pipe 94 flows to the chambers at the back side of both the valve pistons 82 and 83 thereby causing valve piston 82 to maintain the ball valve 8| unseated and also causing the release valve piston 83 to be seated.

Energization of the magnet winding 85 causes the double beat valve 84 to be shifted to its lower seated position in which the supply communica tion from the branch passage N35 to the chambers at the back side of the valve pistons 32 and is closed and the fluid under pressure vented to atmosphere from these chambers through the exhaust port Hit, The supply pressure in chamber 93 effective on the inner seated area of the valve piston 82 is accordingly effective to over come the spring 9i and the valve piston 82 is accordingly shifted downwardly into seated relation on an annular gasket Idt, thereby closing the connection between passage 22 and the chamber at the back side of the valve piston 3'2. The chamber at the back side of the valve piston 82 is connected through a passage ills with the chamber at the back side of the release valve piston 83 and a ball check valve lid is provided in the passagelilil in a manner to permit the exhaust of fluid under pressure past the valve III] from the chamber at the back side of the valve piston 82 and to prevent the reverse flow of fluid under pressure therepast. It will thus be seen that once the valve piston 82 is shifted downwardly into seated relation on the annular gasket I08, the chamber at the back side of the valve piston is isolated at atmospheric pressure and'thus the valve piston is maintained ther eafter in such position by the fluid pressure in chamber 93 acting over the entire outer face thereof against the yielding force of the spring HI. Spring 9| is of such strength as to be ineffective to return the valve piston 82 upwardly into seated relation on the annular rib seat 89 from the annular gasket seat Hi8 unless the pressure acting on the outer face of the valve piston 82 is reduced to a relatively low pressure such as five pounds per square inch.

It should accordingly be understood that when the double beat valve 84 is actuated to its lower seated position upon energization of the magnetwinding 85, the supply of fluid under pressure to the brake cylinders II from the supply reservoir I6 under control of relays I5 is cut off and fluid under pressure is vented from the brake cylinders I I under the control of the release valve 83 through the exhaust port 98 at a very rapid rate. When the magnet winding 85 is deenergized and the double beat valve 84 is returned to its upper seated position, fluid under pressure flows from the passage 94 to the chamber at the back of the release, valve piston 83 past the lower valve seat of the double beat valve 8d so that the release valve piston 83 is substantially immediately restored to seated position on annular rib seat 96 to prevent the further exhaust of fluid under pressure from the passage 94 through the exhaust port 98.

Although fluid under pressure is supplied to the chamber at the back side of the release valve piston 83, check valve H9 prevents flow of fluid under pressure therefromthrough the passage id!) to the chamber at the back side of the valve piston 82 which is maintained in seated relation on annular gasket I98 by the pressure of the fluid in the chamber hus, once the magnet Winding is energiwd, the ball valve 8| is effective to cut off the supply of fluid under pressure to the brake cylinder under the control of the adjusting relay l5 and cannot thereafter be unseated. so as to permit the supply of fluid under pressure to the brake cylinders under the control of the adjusting relay I5 unless the brake cylinder pressure acting to hold the valve piston 32 seated on gasket seat Iilll is substantially completely reduced to atmospheric pressure.

The reapplication magnet valve 24 comprises a casing having a bore I I5, in which a valve piston Ht operates, and a chamber Ill containing a double beat valve H8 which is operated by an electromagnetic winding I l9 through the medium of an associated plunger I2 I or stem fixed to the valve I I8. The valve piston I It is normally urged downwardly into seated relation on an annular rib seat I22 by a coil spring I23 that is interposed between the casing and the back side of the valve piston H6 within the bore H5. The brake cylinder supply pipe M is connected into the space at the inner seated area of the valve piston HG within the annular rib seat i212 and the space at the outer seated area of the valve piston I I6 is connected by a pipe and passage M5 to a supply reservoir 25.

With the double beat valve H8 in its upper seated position, communication is established past the lower valve seat thereof through a branch passage I26 of the passage I25, chamber l i? and a passage 12? connecting the chamber i I1 and the chamber at the back side of the valve I it. Thus fluid under pressure is supplied from the supply reservoir to the chamber at the back side of the valve piston H6 to maintain it in seated relation on the annular rib seat I22.

When the magnet winding I IQ is energized and the double beat valve Iill thus actuated to its lower seated position, the communication just described, through which fiuid under pressure is supplied from supply reservoir 25 to the chamber at the back side of the valve piston I 56 of the reapplication magnet valve id, is closed and fluid under pressure is vented from the chamber at the back side of the valve piston I I6 past the upper valve seat of the double beat valve I 58 to atmosphere through an exhaust port I28. The pressure of the fluid from the supply reservoir 25 acting on the outer seated area of the valve piston l 56 accordingly becomes effective to overcome the spring I23 and shift the valve piston upwardly and unseat it from the annular rib seat I22, thereby establishing communication between supply pipe and passage I25 and the brake cylinder pipe 94.

The brake cylinder pipe 9A is provided with a restricted portion or choke I31 which serves to' control the rate of supply of fluid under pressure P valvepiston I I 6 being almost instantaneously unseated and seated in response to the energization and deenergization of the magnet winding II 9, thereby enabling a very rapid build-up as well as I a very accurate control of the pressure established under the control thereof in the brake cylinders II.

Referring to the drawings, particularly Figs. 3 and 4, it will be seen that a rotary inertia device 22 is provided in associated relation with each car Wheel 50. Each car wheel It may be individually mounted in any suitable manner as for example on an axle I39 which is non-rotatably fixed to the wheel truck frame in a manner not shown and disposed transversely of the car and track rails in the manner similar to the usual rotating axle, a pair of wheels I0 being supported at opposite ends respectively of a single axle for rolling on the opposite rails of the car track. Suitable anti-friction bearings, such as the ball bearings I32 shown, may be provided for rotatably mounting the car wheels E6 on the axle I30. The hub portion I33 of each car wheel IIl may be provided with a suitable bushing I34 having a flange I35 at the inner end thereof which engages a shoulder 236 on a sleeve 53? fixed to the axle, for the purpose of limiting the inward movement of the car wheel I9 along the axle.

Each rotary inertia device comprises a rotary inertia element or ring I39 rotatably mounted on the hub portion I33 of the car wheel I9 through the medium of ball bearings MI and driven by rotation of the car wheel through a flexible resilient connection in the form of a leaf spring I42.

As shown clearly in Fig. 3, the inertia ring I39 is provided on the internal surface thereof with a peripheral groove indicated as semi-hexagonal in cross-section and concentrically disposed within the inertia ring I99 is another ring member I44 having a complementary peripheral groove of corresponding semi-hexagonal cross-section, the ball bearings I4! being received in the closed groove formed by the two registering grooves I43 and I45 through a transverse slot I46 in the inertia ring E99 and each ball bearing I4I being held in position by means of bifurcated or forked members I47 of L-shape secured to the inertia ring as'by screws M3.

The ring I44 is fixed to a tubular member I49 through a cushioning ring I5! of suitable material, such as rubber, which is suitably bondedon the outer and inner surfaces thereof to the ring I44 and tubular member I49 respectively. The tubular member I49 is adapted to fit closely over the inner end of the hub portion I33 of the arms is shown in Fig. 3, fixed to or integrally formed on the ring 44. The arrangement of the lug I54 and the yoke arms I55 on the ring I44 is such as to permit a limited maximum rotative movement of the inertia ring I39 relative to the ring I44 and the car. wheel I9.

Suitably carried on the tubular member I49, at a portion of reduced diameter, is an insulating block I59 whichlmay be fixed or secured to the tubular member I 49 as by a plurality of bolts I51. The insulating block I56 has suitably secured therein a metallic U-shaped member I 58 in which one end of the leaf spring I42 is slidably received,

the other end of the leaf spring being riveted or otherwise suitably clamped between the flanges of two L-shaped brackets I6! fixed to the outer periphery of the inertia ring I39 in insulating relation thereto as by screws I62. I

Carried by the insulating block I56 are a plurality of contact fingers, three contact fingers I63a, H3411, I65a, respectively being provided on one side and three contact fingers I631), I642) and 965b, respectively on the opposite sides of the leaf spring I42. 1

Each contact finger is in the form of a bell crank lever pivoted at the fulcrum thereof on a pin I6? of insulating material, a coil spring confined in a suitable circular recess in the insulating block I56 urgingan arm of the contact finger to a position limited by engagement with a stop screw I 59. Suitable insulating washers or spacing rings I II of insulating material are provided between the adjacent contact fingers on a pivot pin I67.

The stop screws i 99 for the different contact fingers are adjusted to different positions so that normally the contact fingers in each group on opposite sides of the leaf springs are displaced successively increasing or decreasing distances from cooperating contact discs I12 fixed on the metallic leaf spring I42. When a car wheel is decelerated or accelerated, the inertia ring I39 tends to over-run o-r under-run the car wheel and consequently, depending upon the rate of deceleration or acceleration shifts rotatively relative to the car wheel different degrees, so that engagement of each of the contact discs I12 of the leaf spring I42 with a corresponding contact finger will accordingly take place at different rates of acceleration or deceleration. For example, referring to Fig. 1, if the car wheels II! are rotating in a counterclockwise direction for forward motion of the car or train, the inertia ring I39 will tend to over-run its associated car wheel I 6 in a counterclockwise direction and thus effect successive engagement of the leaf spring I42 with the contact fingers I632), I642) and i651) located to the left of the leaf spring I42.

The tension of the spring I42 and the adjust-- ment of the contact fingers may be such, for example, that engagement of the contact finger 56911 with the leaf spring I42 occurs at or above a rate of rotative deceleration of the vehicle wheel corresponding substantially to a rate of deceleration of the car of 4.4 miles per hour per second, engagement of the contact finger I641)- with the leaf spring I42 occurs at or above a rate of rotative speed of deceleration of the car wheel corresponding substantially to a rate of retardation of the car of 5.5 miles per hour per second, and engagement of the contact finger I651) with the leaf spring I42 occurs at or above a rate of rotative deceleration of the car wheel I9 corresponding substantially to a rate of .deceleration of the car of 7.7 miles per hour per second. It should be understood that the above figures used are illustrative only and that the adjustment of the contact fingers and the tension of the leaf spring I42 may be such that engagement of the leaf spring with the contact fingers occurs at any desired successive rates of rotative deceleration of the car wheel.

In a similar manner the adjustment of the contact fingers I63a, Ifida, and IBM respectively is such that the flexing of the leaf spring I 42 due to the shifting of the inertia ring I39 backwardly of its normal position with respect to the car wheel upon acceleration of the car wheel results in the successive engagement of the contact discs I12 on leaf spring I42 with the contact fingers IIiSa, I 640. and I 65a respectively at rates of rotative acceleration of the car wheel corresponding to 4.4, 5.5 and 7.? miles per hour per second retardation of the car.

It should be understood that if the car wheel I0 is rotating in a clockwise direction upon deoeleration of the wheel, then the contact fingers I63a, lfi la and 25a are successively engaged according to the rate of deceleration of the wheel and the contact fingers I631), I041), I651) are successively engaged according to the rate of acceleration of the vehicle wheel.

As will be made apparent hereinafter, I pro-* vide electrical means under the control of the switches formed by the leaf spring I42 and the respective contact fingers associated there ith to control the degree of application of the brakes, that is, the brake cylinder pressure. In order to establish an electrical connection to the contact fingers 163a, IBM, IBM, H531), I541) and i651 and to the leaf spring I 12, four collector or slip rings I12, I13, I14 and I15 are mounted in insulated relation on the tubular member its in concentric relation to the axle I30. As will be seen in Fig. 3, the slip rings I12 to I15 disposed side by side and provided at intervals with suitable bushings and spacers of insulating material through which bolts I12 extend for fastening the rings to a flange at the end of tubular member I that extends radially inward toward the axle I30.

The metallic member I58, in which the inner end of the flexible spring M2 is held, is connected to one of the slip rings, such as I12, by a suitably insulated wire I11.

Each contact finger is provided with a terminal strap or post I10 (see Fig. 4) fixed in the insu- 1.; lating block I56 and adapted to be engaged by the coil spring I58 which yieldingly urges the corresponding contact finger to its normal sition. Short insulated wires I03, I84 and IE5 connect the terminal strap I18 of contact fin gers I63a, lt la and I65a to slip rings I13, I14

and I15, respectively. Similarly, short insulated wires I85, I84 and I85 connect the terminal straps of contact fingers I631), I641) and IE5?) to slip rings I13, I14 and I15, respectively. Thus, corresponding contact fingers on opposite sides of the leaf spring are connected to each other by virtue of connection to the same slip ring.

Associated with the slip rings I12, I13, I14 and I 15 is a brush holder I81 for supporting a plurality of brushes I92, I93, I94 and I95 in contact with the slip rings I12 to I15, respectively, in well known manner, the brush holder I81 being mounted stationarily as on a bracket I88 secured by screws I89 to a split ring I90 detachably se- 3? cured in clamping relation around the sleeve I31 on the axle I3I. Wires 202, 203, 204 and 205 are connected respectively to the brushes I92 to I95, each of the wires 202 to 205 being suitably insulated and preferably all bound together in a single unitary cable 206 leading into the brush holder I81.

For simplicity and clarity, the wires 202, 203, 204 and 205 are shown in Figs. 1 and 2 as connected directly to the contact fingers I63a to I65a, I631) to I851) and leaf spring I42 without any representation of the slip rings I92 to I95 or brush holder I81.

A suitable casing 2I I split into two portions having flanges adapted to meet and to be secured together substantially in a horizontal plane extending through the center line of the axle I30, as indicated at the right of Fig. 3, is provided for housing the inertia ring I29 and other parts of the rotary inertia devices 22. The two portions of the casing ZII may be secured to the hub portion of the car wheel III as by screws 2l2, in the manner shown in Fig. 3, in which case the casing 2H rotates with the car wheel, or the casing 2 may be suitably attached to the non-rotatable axle I35 in manner not shown, in which case the casing 2II does not rotate. In any case, the cable 268 containing the wires 202 to 205 extends out of the casing 2M preferably at the central opening 2I3 through which the axle I30 extends so as not to interfere with the rotation of the casing.

As indicated in Figs. 1 and 2 the rotary inertia devices 22 associated with all the wheels of truck Nov I are connected in parallel relation and the rotary inertia devices of truck No. 2 are all connected in parallel relation, the wires 202, 203, 204 and 205 leading out of each rotary inertia device being connected to common wires 222, 223, 224 and 225, respectively.

The Wires 222 and 223 are the same for both indicated, the direction coordinator 2% comprises A three electromagnetic relays or switch devices 21, 28 and 22. Relay 21 is illustrated diagrammatically as comprising an electromagnet winding 221 eifective when ener ized to actuate an armature, illustrated in the form of a stem or plunger 228, from an upper position to which it is urged by a coil spring 229 to a lower position against the yielding resistance of the spring 229. Armature 228 carries in insulated relation thereon two contact members 23! and 222. Associated with the contact member 23! are two pairs of fixed contact members 2am and 23H), respectively, and associated with the contact member 222 are two pairs of contact members 232a and 232b, respectively. In the normal or upper position of the armature 228, the contact members 231 and 232 respectively engage the pairs of contact members 23Ia and 222a in circuit-closing contact. In the lower or actuated position of the armature 228, the contact members 231 and 232 disengage the associated contact members 2am and 232a and respectively engage the pairs of contact members 2311) and 2222) in circuit-closing contact.

The relay 2% comprises an electromagnet winding 224 elTective, when energized, to actuate an armature indicated in the form of a plunger 235, from an upper position to which it is normally urged by a coil spring 236 to a lower or actuated position. The armature 225 carries in insulated relation thereon two contact members 231 and 238. Associated with the contact member 231 are a pair of fixed contact members 231a which are engaged by the contact member 231 only when the armature 235 is in its actuated position. Associated with the contact member 238 are a battery 3! may be of the order of 6 volts.

pair of fixed upper contact members 233a and a pair of fixed lower contact members 23th. In the normal position of) the armature 23.5, the contact member 238 engages the contact members 238a in circuit-closing contact. In the actuated position of the armature 235 the contact member 238 disengages the contact members 2 55a and engages the contact members 2382) in circuitclosing contact.

The relay 28 is of the slow pick-up type and to indicate this characteristic of the relay 28, a lag ring 239 is disclosed in associated relation with the armature 235 which functions to delay for a slight interval of time the movement of the armature 235 in response to the initial energization of the electromagnet winding 234. The purpose of the slow pick-up characteristic of relay 28 will be made clear hereinafter.

The relay 29 comprises an electromagnet winding 24! which is effective, when energized, to actuate an armature illustrated in the form of a stem or plunger 232, from a normal position to which it is urged by a coil spring 243 to a lower actuated position. The armature zs-zcarries in insulated relation thereon a contact member 2% which engages a pair of associated fixed contact members Z l ion when the armature is in its normal upper position and which disengages the contact members M lo and engages a pair of associated fixed contact members 2441] when the armature is in its actuated position.

The various relays 21, 28 and 29 of the direction coordinator 26 are associated and related electrically in a manner to be more fully described hereinafter in connection with an assumed operation of the equipment. Briefly, however, the direction coordinator 26 is effective to cause the rotary inertia devices 22 associated therewith to always effect operation first of the slip magnet valve 23 and then of the reapplication magnet valve whether the vehicle wheels I!) are rotating in one direction or the other.

As indicated by the number of cells making up each of the batteries 3!] and 3!, the battery 3!] has a higher voltage and current capacity than the battery 3 I. As will be explained more fully here-. inafter, the synchronizing train wire is energized by current supplied from the battery 38, while the various electromagnet windings, particularly those under the control of rotary inertia devices 22, are energized by current supplied from the battery 3!. As a practical matter, the battery 30 may have a terminal voltage of for example 32 volts whereas, the terminal voltage of the It should be understood that while the batteries 30 and 3! are indicated as separate units, a single battery may be provided having suitable terminal connections to provide the desired supply voltages and current capacity of the two batteries 39 and 3!.

The reason for providing a source of higher voltage for energizing the synchronizing train wire is to insure sufiicient current for energizing the electromagnet winding of the relays 36, the synchronizing train wire being possibly of high resistance due to poor connections between cars. The reason for employing a source of lower voltage for energizing the electromagnet windings subject to the control of the rotary inertia devices 22 is to avoid the necessity for high current carrying capacity of the contact fingers of the rotary inertia devices as well as to minimize burning or pitting of the contact fingers due to arcing.

The pressure-operated switch 32- may be of any suitable construction and, as illustrated diagrammatically, may comprise a casing containing a piston 25! having a stem 252 carrying in insulated relation thereon a contact member 253, with which is associated a pair of fixed contact members 255. Interposed between the piston 25! and the casing is a coil spring 255 which normally urges the piston to a limited position in one direction in which the contact member 253 disengages its associated contact members 254. On the side of the piston 25! opposite the spring 255 is a chamber 256 which is connected through a branch pipe 25? to the fiuid pressure supply pipe 258 leading to the two adjusting relays !5, which pipe 258 is in turn connected through a branch pipe 259 to the volume reservoir !8.

The strength of the spring 255 is such as to maintain the contact member 253 out of engagement with its associated contact members 25 3 until the pressure in, the volume reservoir 18 effective in the chamber 256 on the piston 25! exceeds a certain low pressure, such as five pounds per square inch, after which the spring yields in response to the fiuid pressure and permits movement of the piston 25! to effect engagement of the contact member 253 with its associated contact members 254. When the piston 25! is unseated downwardly from its normal position, the area thereof subject to the pressure in the volume reservoir !8 is suddenly increased and accordingly the contact member 253 is snapped into contact with its associated contact members 254.

The pressure switch 32 is provided for controlling the connection from one terminal of the battery 3!, hereinafter called the positive terminal, to the wire 222 previously referred to and to which all of the wires 292 from the rotary inertia devices 22 are connected. As shown in Fig. 2, one of the contact members 25 1 of pressure switch 32 is connected to the wire 222 by a branch wire 262 and the other contact member 254 is connected to the positive terminal of the battery 3! by a wire 263 in which is interposed, in series relation, the inductance coil 33.

It will accordingly be seen that unless the pressure established in the volume reservoir H3 in response to the operation of the brake valve M exceeds the relatively low pressure of five pounds per square inch, no current can be supplied from the battery 3!. With a pressure established in the volume reservoir it that is in excess of the five pounds per square inch, the contact member 253 of the pressure switch 32 connects the wires 262 and 263, thereby connecting the positive terminal of the battery 3! to the wire 222 and enabling current to be supplied from the bat tery 3!.

The inductance coil 33 functions to delay for a slight interval of time, of the order of a fractional part of a second, the supply of current from the battery 3!. The reason for such delay will be made apparent in the subsequent description of the operation of the equipment.

The relays 35 and 36 may be of any suitable construction including an electromagnet winding effective upon energization to actuate an associated contact-carrying armature. As indicated diagrammatically, the relay 35 may comprise an electromagnet winding 350, effective, when energized, to actuate an armature carrying in insulated relation thereon a contact member 35?) to effect engagement of the contact member with a pair of associated contact members 350.

With

the electromagnet winding 35a deenergized, the armature is biased by gravity or by spring means not shown to a normal position in which the contact member 352) disengages the contact members 350. In a similar manner, the relay 36 comprises an electromagnet winding 36a efiective, when energized, to actuate a contact member 36b into contact with a pair of associated fixed contact members 360.

The supply reservoir I6 is connected to and charged with fluid under pressure from the main reservoir pipe I! through a branch pipe 266 in which is included a one-Way or check valve 25'! for preventing back flow of fluid under pressure from the reservoir to the pipe. In a similar manner the two supply reservoirs 25 on each car are charged with fluid under pressure from the main reservoir pipe I? through corresponding branch pipes 258 connecting the corresponding inlet pipes M5 for the reservoirs 25 and the main reservoir pipe ii, a one-way or check valve 269 being included in each of the pipes 268 for preventing back flow of fluid under pressure from the reservoirs. If desired a single large capacity supply reservoir may be provided instead of the three reservoirs. The provision of three separate reservoirs as shown avoids unnecessary long stretches of pipe, since the supply reservoirs 25 may be located at the respectively associated wheel trucks while, if only one reservoir is employed, it would be located midway between the two trucks at opposite ends of a car.

OPERATION (a). Application of the brakes, including untomcttic regulation of rate of retardation Let it be assumed that the main reservoir I3 is charged to the normal pressure carried therein, from a fluid compressor not shown, that all the sup-ply reservoirs I6 and 25 on all of the cars are also correspondingly charged to the normal pressure carried therein, that the brake valve handle ii is in its normal brake release position so that the brakes on the car or train are all released, that the car or train is traveling under power or coasting in the left-hand direction, as viewed in Figs. 1 and 2, so that the car wheels It rotate in a counterclockwise direction, and that the operator desires to efiect an emergency application of the brakes.

To effect an emergency application of the brakes, the operator shifts the brake handle 4i out of its normal release position into its emergency position. Fluid under pressure is accordingly supplied from the main reservoir to the straight-air pipe I2 to establish the maximum pressure therein corresponding to the pressure in the main. reservoir, fluid under pressure flowing from the straight-air pipe I2 through the branch pipe 53 on each car, past the unseated ball valve of the cut-ofi magnet valve I9, through passage pipes and 56 to the volume reservoir is and thence by way of the pipes 259 and 258 to the pressure chambers of the relays IE. The relay it for wheel truck No. 1 is accordingly operated in response to the pressure established in the volume reservoir I8 to cause fluid under pressure to be supplied from the supply reservoir it through the supply pipe 81 past the unseated ball valve SI of the slip magnet valve through chamber 93, passage and pipe 9t and pipe 95 to the brake cylinders I I associated with the forward and rear pairs of vehicle wheels of truck No. 1, the relay I5 being automatically operative according to the setting thereof to establish a pressure in the brake cylinders I corresponding to the pressure established in the volume reservoir I8. In a similar manner, the relay I5 for the wheel truck No. 2 is operative in response to the pressure established in the volume reservoir I8 to cause fiuid under pressure to be supplied from the supply reservoir it to the brake cylinders II of wheel truck No. 2, the pressure established in these brake cylinders being according to the pressure established in the volume reservoir it and according to the setting of relay I5. If the load carried by the two wheel trucks No. 1 and 2 is the same, the relays I5 for each truck will be set identically and accordingly the same pressure will be established in the brake cylinders ii for both Wheel trucks. If, however, the load carried by wheel truck No. l is greater than that carried by truck No. 2, then due to the different setting of the relay It for the truck No l, the pressure established in the brake cylinders I l of truck No. 1 will be correspondingly greater, although the pressure established in all brake cylinders is determined by the pressure established in the volume reservoir 58.

The pressure switch 32 is operated to connect the battery 3| to the wire 222, whenever the pressure in volume reservoir I8 exceeds the predetermined low value of five pounds per square inch. However, as will be apparent hereinafter, no current is supplied or drawn from the battery 3i unless one or more of the rotary inertia devices 22 associated with the car wheels It is operated sufiiciently in response to the rotative retardation of the car wheels.

It will be apparent that all of the car wheels II] will be rotatively decelerated at substantially the same rate in response to the application of the brakes effected by the supply of iiuid under pressure to the brake cylinders I I.

Let it be assumed that the rate of rotative deceleration of the car wheels It eifected by the application of the brakes attains a value corresponding for example to a rate of retardation of the car or train of 4.4 miles per hour per second so that the rotary inertia devices 22 associated with the different car wheels I d of the two wheel trucks all respond to effect the engagement of the leaf spring I42 thereof with the contact finger I631) at substantially the same instant.

Since, as a practical matter, all inertia devices will not respond identically, let it be assumed that one of the rotary inertia devices 22, such as that associated with the car wheel It at the lefthand end of wheel truck No. 2 in Fig. 2, is the first to effect the engagement of the leaf spring Hi2 thereof with its contact finger 163% In such case, a circuit is completed for energizing the electromagnet winding 58 of the cut-oil magnet valve I9, this circuit extending from battery wire 222, connected to the positive terminal or" the battery 3| as previously described, wire 202 leading to the inertia device 22 of the car wheel I0 at the left-hand end of truck No. 2 to the leaf spring I42 thereof and thence through the contact finger I632) and wire 203 leading out of the rotary inertia device, wire 223, electromagnet winding 58, to the negative terminal of the battery 3I through a ground connection in the manner indicated. As previously explained, the energization of the magnet winding 58 of the cut-off magnet valve I9 operates the double beat valve 5? to rapidly vent fluid under pressure from the back side of valve piston 41 to cause it to be shifted downwardly to effect the immediate seating of the ball valve 45 to cut oi? the further supply of fluid under pressure from the branch pipe 53 to the volume reservoir I8. Thus, notwithstanding that the pressure in the straight-air pipe I2 may continue to increase, no further fluid under pressure can be supplied from the straight-air pipe to the volume reservoir 23 unless the ball valve 45 is again unseated. The unseating of the ball valve 45 can only take place in the event that the magnet winding 58 is again deenergized, as subsequently described.

All of the rotary inertia devices 22 associated with all of the car wheels it are connected in parallel relation so that the engagement of the leaf spring I42 thereof with the corresponding contact finger I532) connects the battery wire 222 to the wire 223 leading to the electromagnet winding 58 of the cut-off magnet valve. It will thus be apparent that anyone of the rotary inertia devices 22, depending upon which first completes the circuit, is adapted to energize the magnet winding 38 of the cut-01f magnet valve i9 initially. Thus as those inertia devices 22, after the first, are operated to connect the battery wire 222 to the wire 223 a plurality of parallel circuits are established between the battery wire 222 and the wire 223 but the operation of any inertia devices after the first is without initiatory effect.

As is well known, the coefficient of friction between the brake shoes and the tread or other braking surface of the car wheels it! increases as the speed of rotation of the car wheels decreases so that for a given pressure established in the brake cylinders I I, the rate of rotative deceleration of the car wheels It tends to increase after the cut-off magnet valve is on each car is operated to limit the pressure established in the volume reservoir I8 on the coresponding car.

When the rate of rotative deceleration of the car wheels III of either of the trucks No. 1 or No. 2 attains a value corresponding to a 5.5 miles per hour per second rate of retardation of the car or train, and the leaf spring I42 of one of the inertia devices 22 engages its associated contact finger I645, a circuit is completed for energizing the synchronizing train wire 34. This circuit is not established directly under the control of the rotary inertia devices 22 but indirectly through the relay 35. Upon the engagement of the leaf spring I42 of one or more rotary inertia devices 22 with the contact finger I645, a circuit is completed for energizing the magnet winding 35a of the relay valve 35, this circuit extending from the battery wire 222 through the wire 232 and leaf spring I42 of the first operated rotary inertia device to contact finger I645 thereof, thence through wires 264 and 224, contact members 96a and 90 of the slip magnet valve 23 for the corresponding truck, wire 215, magnet winding 35a and to the negative terminal of the battery 3| as through a ground connection in the manner indicated.

Upon the energization of the magnet winding of the relay 35, contact member 35b of the relay is actuated into engagement with the associated contact members 355 to connect one terminal of the battery 30, hereinafter referred toas the positive terminal, to the synchronizing train wire 34 through the simple connection shown in the upper left-hand corner of Fig. 1.

The magnet winding 36!], of each of the relays 36 has one terminal thereof connected to the synchronizing train wire and the other terminal is connected to the negative terminal of the battery 30 as through a ground connection in the manner shown. Accordingly, all of the relays 36 on all of the cars throughout the train are simultaneously energized and actuated to circuit-closing position.

7 By the time that any one of the car wheels IIJ attains a rate of rotative deceleration corresponding to retardation of the car or train at a rate of 5.5 miles per hour per second, all of the car wheels will have attained a rotative deceleration rate corresponding at least to 4.4 miles per hour per second retardation of the car or train. Thus upon the actuation of the relay 36 on each car to circuit-closing position, a circuit is established for energizing the magnet winding I? of the release magnet valve 2| on each car, this circuit extend? ing from the wire 223, which as previously explained is connected to the battery wire 222 through the contact fingers I631) and spring I42 of the rotary inertia devices 22, through a wire 2'", contact members 36b and 360 of the relay 36, wire 21B, magnet winding TI of the release magnet valve 2I, to the negative terminal of the battery 3I through a ground connection in the manner indicated.

As previously explained, the energization of the magnet winding T! of the release magnet valve 2I causes the valve piston 66 of the release magnet valve 2I to be unseated to vent fluid under pressure from the volume reservoir is at a restricted rate determined by the size of the choke passage in the exhaust port II. The volume reservoir I8 is of sufiicient capacity, in relation to size of the choke passage of the exhaust port II, as to cause the pressure in the volume reservoir I8 to be reduced gradually at a relatively slow rate to prevent over-reduction of the operating pressure for the relays I5.

As the pressure in the volume reservoir I8 on each car reduces under the control of the corresponding release magnet valve 2I, the relays I5 for each of the wheel trucks Nos. I and 2 on each car are correspondingly operated to release fiuid under pressure from the brake cylinders II in a reverse direction through the pipe 35, pipe and passage 94, past the ball valve 8| of the slip magnet valve 23, pipe 81 to atmosphere at the relay I5.

The reduction in the pressure established in the brake cylinders accordingly uniformly reduces the degree of application of the brakes on all of the car wheels I0 of all of the wheel trucks throughout the train. Accordingly, the rotary inertia devices 22 associated with the car wheels Ill respond promptly to the reduced degree of application of the brakes sufficiently to effect the disengagement of leaf spring I42 thereof from the contact finger I641). When the rotary inertia devices 22 for all of the car wheels of all the wheel trucks on any one car have all operated so as to effect the disengagement of the leaf spring I42 thereof from the associated contact finger I645, the circuit for energizing the magnet winding of the relay 35 on that car is interrupted. The relay 35 is accordingly actuated to circuit-opening position, thereby disconnecting the battery from the synchronizing train wire 34.

The magnet windings 36a of all of the relays 36 will remain energized, however, as long as there are any rotary inertia devices 22 associated with any of the wheels throughout the train effective to maintain energization of the synchronizing train wire 34. When the relays on all cars have been operated to disconnect the associated batteries 3|! fromthe synchronizing train wire 34, all of the relays 36 are simultaneously v of the corresponding release magnet valve 2 I. As

previously explained, the valve piston 66 of the release magnet valve 2! is promptly reseated in response to the deenergization of the magnet winding ll to cut off the further venting of fluid under pressure from the volume reservoir ii! on the corresponding car.

It will thus be seen that the arrangement and circuit connections of the rotary inertia devices 22 associatedwith all of the car wheels is such as to prevent any car wheel from being rotatively decelerated at a rate in excess of 5.5 miles per hour per second, assuming of course that a wheel does not begin to slip-in which case a different operation occurs as will be explained hereinafter. It will accordingly be seen that the rotary inertia devices 22 operate automatically to regulate the rate of rotative deceleration of the car wheels I0 to a value corresponding to a rate of deceleration of the train somewhere between 4.4 miles per hour per second and 5.5 miles per hour per second. It will be apparent that such is the case because the instant that any one wheel ill reaches a rate of rotative deceleration which is the equivalent of 5.5 miles per hour per second rate of retardation of train, the synchronizing train wire 34 is energized and a reduction of volume reservoir pressure efi'ected so as to effect a corresponding reduction of pressure in the brake cylinders i I associated with all of the car wheels throughout the train. During any one application of the brakes, the rotary inertia devices 22 may function repeatedly .to energize the synchronizing train wire 34 and thus repeatedly reduce the pressure in the brake cylinders I to maintain a substantially uniform. rate of rotative deceleration of the individual car wheels and consequently a substantially uniform rate of retardation of the train.

Whenthe car or train has been brought to a complete stop in response to the application of the brake, the inertia ring I39 of every rotary inertia device 22 is restored to its normal position. Thus the circuit previously described for energizing the magnet winding 58 of the cut-off magnet valve E9 on each car under the control of the leaf spring I42 and contact finger 1 53b of each rotary inertia device on the corresponding car is interrupted and consequently the valve piston i! is shifted upwardly to unseat the ball valve 45.

In View of the reduction in the initially established pressure in the volume reservoir i8 due to operation of the release magnet valve2l, the unseating of the ball valve 45 of cut-off magnet valve IS on each car causes fluid under pressure to be again supplied from the straight-air pipe 52 to the volume reservoir 18 to rebuild the pressure therein to a pressure corresponding to that established in the straight-air pipe 82 and thus increase the degree of application of the brakes. With the car or train stopped however such increase of the degree of application of the brake is on the safe side since it is eifective to hold the car or train more effectively against creepage on a grade. I

In the foregoing operation it was assumed that the rotary inertia devices 22 function to regulate the rate of retardation of the wheels of the train during an emergency application of the brakes to a substantially uniform rate somewhere between 4.4 and 5.5 miles per hour per second. As a practical matter, the rotary inertia devices would not be effective during a service applica tion of the brakes to regulate the rate of retardation of the car wheels because the degree of application of the brakes during a service application would not be sufiicient to produce a rate of retardation of the train as high as 4.4 miles per hour per second, the rate at which it was here assumed the operation of cut-off magnet valve E9 was efiected.

It should be understood, however, that if it desired to regulate the rate of retardation of the train during a service application of the brakes, the rotary inertia devices may be designed. so as to eifect operation of the cut-off and release magnet valve devices l9 and 2| at lower rates of retardation of the train, such as 2.5 and 3.5 miles per hour per second, respectively.

(b) Prevention of wheel-sliding In the foregoing hypothetical operation, it was assumed that none of the car wheels IE1 slipped during the application of the brakes, It is now proposed to describe the manner in which the equipment operates in the event that a car wheel begins to slip during application of the brakes, whether it is an emergency or service application thereof.

Let it be assumed that an application of the brakes has been initiated, as previouslyv described, and that the rotary inertia devices 22 are operating in the manner previously described to regulate the rate of retardation of the car wheels and consequently of the car or train to a substantially uniform rate according to the design, adjustment and. setting of the rotary inertia devices, assumed for illustrative purposes in the present application to be between 4.4 and 5.5 miles per hour per second. Let it be further assumed that the car wheel [0 shown at the lefthand end of truck No. 1 begins to slip during the application of the brakes. As is well known, when a car wheel begins to slip it decelerates at an exceedingly fast rate, attaining values sometimes as great as twenty to twenty-five miles per hour per second momentarily. Thus, when the car wheel If! has attained a rotative deceleration rate of 7.7 miles per hour per second, the increased displacement of the inertia ring iEB of the rotary inertia device associated with the wheel i3 further flexes the leaf spring #12 and causes it to engage the contact finger 852). A circuit is thereby completed for energizing magnet windings 24! and 234, respectively, of the relays 29 and 28 of the direction coordinator 2% for the corresponding wheel truck, and also the magnet winding 85 of the slip magnet valve 23 for the corresponding wheel truck. This circuit extends from the battery wire 222 through the wire 292 to the leaf spring Hi2 of the rotary inertia device 22 associated with the slipping wheel Ill, thence by way of the contact finger I655, wire 255 leading out of the rotary inertia device 22, wire 225, a Wire 285, contact members 232a and 232 of the relay 2? of the direction coordinator 2%, a wire 28% magnet winding 24! of the relay 29, wires 23'; and 288, contact members 238a and 23% of the relay 28, a wire 289, in parall l through magnet winding of the slip magnet valve 23 and magnet winding 234 of relay 2%, and to the negative terminal of the battery 32 as through a ground connection in the manner indicated.

Since the magnet Winding 234 of the relay 28 and the magnet winding 85 of the slip magnet valve 23 are in parallel relation, they are accordingly simultaneously energized. Due to the slow pick-up characteristic of relay 28, as effected by the lag ring 239, the contact member 238 of relay 28 is not immediately actuated to interrupt the circuit for energizing the magnet winding 85 of'the slip magnet valve 23, thus assuring full energization of the magnet winding 85 of the slip magnet valve 23 and of the magnet winding 234 of relay 28.

When the armature 2350f the relay 28 is shifted to its actuated position in response to the energization of the magnet winding 234, the circuit through the contact members 238 and 238a of the relay 28 is interrupted but, at the same time, a holding circuit is established by the engagement of the contact member 231 of relay 28 with its associated contact members 231a and, consequently, the magnet winding 234 of the relay 28 as well as themagnet winding 85 of the slip magnet 'valve 23 remains energized. The holding circuit for the magnet windings 234 and 85 extends from the battery wire 222 through contact members 23Ia and 23I of the relay 21, a wire 29L contact members 231a and 231 of relay 28, a wire 292, wire 289, in parallel through 1 the magnet windings 234 and 85, and to the negative terminal of the battery 3I through the ground connection indicated. It should be understood that once the magnet winding 234 of relay 28 is fully energized, the armature 235 of the relay is shifted so positively and rapidly as to effect engagement of the holding circuit contact member 2311 with contact members 231a, notwithstanding the momentary interruption of the circuit between the time that contact member 238 opens the circuit and contact member 231 establishes the holding circuit.

When the relay 29 is actuated in response to the energization of the magnet winding 24!, it establishes a self-holding circuit which is the same as the energizing circuit therefor, previously traced, to the magnet winding MI and thereafter through wires 281 and 288, contact members' 244 and 244?) of the relay 29, a resistor 295, to the negative terminal of the battery 3| as through a ground connection in the manner indicated. The resistor 295 is effective to reduce the current energizing the magnet Winding 24! of the relay 29 to a value sufficient to maintain it in its actuated position without overheating the winding 24!.

Upon the energization of the magnet winding 85 of the slip magnet valve 23, the valve piston 82 is shifted downwardly into seated relation on the annular gasket seat I88 and the chamber at the back of the valve piston 82 continues to be vented to atmospheric pressure by way of the passage I89, past the check valve I I8, and through the exhaust port I86, the brake cylinder pressure effective in the chamber 93 on the upper face of the valve piston 82 pneumatically holding the valve piston 82 in seated position on the annular gasket seat I88 against the pressure of spring 9!. It will thus be apparent that once magnet winding 85 is energized, the valve piston 82 is pneumatically maintained or stuck in its lower position so that the ball valve BI is thereafter seated to prevent the further supply of fluid under pressure to the brake cylinders, under the control of the relay I5, from the supply reservoir I8. At the same time the disengagement of the contact member 98 on the stem 88 of the valve piston 82 from its associated contact members 98a prevents the energization of the magnet winding a of the relay 35 because it interrupts the energizing circuit previously described and establish'ed'by the engagement by the leaf spring I42 with'contact finger I641) of the rotary inertia device 22 associated with the slipping,

wheel. Accordingly, the undesired energization of the synchronizing train wire 34 is prevented when an individual car wheel slips.

It will be understood that current may be supplied momentarily to the magnet winding 35a because the leaf spring I42 engages the contact finger. I 34b of the rotary inertia device associated with the slipping wheel prior to its engagement with its associated contact finger I651). Due, however, to the inherent operating lag of the relay 35, the contact member 35b thereof is not actually shifted to a position connecting the battery 38 to the synchronizing train wire before contact member 98 of the slip magnet valve is actuated to open the circuit for energizing the magnet winding 35a.

As pointed out in the previous description of the slip magnet valve 23, the energization of the magnet winding 85 is also effective to cause the unseating of the release valve piston 83 so that, substantially simultaneously with the seating of the ball valve 8I to prevent the supply of fiuid under pressure therepast to the brake cylinders Il, release piston 83 is unseated to cause fiuid under'pressure to be rapidly vented from the brake cylinders II associated with the wheels of the truck having the slipping wheel, (here assumed to be truck No. 1) through the relatively large exhaust port 98 of the slip magnet valve 23.

The reduction of the pressure in the brake cylinders I I of the wheel truck No. 1 having the slipping wheel is eifected at such a rapid rate through the exhaust port 98 of the'slip magnet valve 23 that the slipping wheel immediately responds to the decrease in the degree of application of the brakes, ceases to decelerate, and then accelerates at a rapid rate back toward a speed corresponding to the speed of the car or train.

' When the slipping car wheel of truck N0. 1 ceases to decelerate at a rate in excess of 7.7 miles per hour per second and theleaf spring 142 of the associated rotary inertia device 22 disengages the contact finger I851), the holding circuit for the relay 29 of the direction coordinator 26 is interrupted. The relay 29 is accordingly returned to its normal position in which the contact member 244 thereof engages the contact members 244a. Since the magnet winding 234 of the relay 28 is still maintained energized by the holding circuit through the contact members 23! and 23Ia of the relay 21 as previously pointed out, the contact member 238 'of the relay 28 remains in contact with its associated contact members 238T).

As is well known, when a slipping wheel returns back toward a speed corresponding to car or train speed, it-accelerates very rapidly, in fact more rapidly than it decelerates at the time slipping is initiated. Accordingly, when the slipping wheel accelerates rotatively back toward a speed corresponding to car or train speed, it does so at a rate in excess of 7.7 miles per hour per second, so that the inertia ring I39 of the associated rotary inertia device 22 shifts backwardly of its normal position to effect engagement of the leaf spring I42 with the contact finger 8655a. A circuit is. thereby completed for energizing the magnet winding 221 of the relay 21, which circuit extends from the battery wire 222 through wire 282 leading into the rotary inertia device 22 associated with the slipping wheel,

the leaf spring I42, contact member I 65a, wires 205, 225 and 285, contact members 2381) and 238 of the relay 28 of the direction coordinator 2%, a wire 296, contact members 2 and 244a of the relay 29, a wire 291, a branch wire 293, magnet Winding 22! of relay 21, and to the negative ter minal of the battery 3! through a ground connection in the manner indicated.

The relay 27 is promptly shifted to its actuated position in response to the energization of its magnet winding 22?. In shifting to its actuated position, the contact member 23! of the relay 21 disengages its associated contact members 2am and thus interrupts the holding circuit, previously traced, for the magnet winding 2% of the relay 28 and the magnet winding 85 of slip magnet valve 23. At the same time, in its actuated position, the contact member 23! engages the associated contact members 23th and thereby establishes a circuit connecting the magnet winding MS of the reapplication magnet valve 22 3 in parallel with the magnet winding 22'! of the relay 2?, which winding H9 is thus promptly energized.

When magnet winding 85 of slip magnet valve 2-3 is deenergized, the release valve piston 83 is instantly restored to seated position closing the exhaust port 98 and further release of fluid under pressure from the brake cylinders H is thus instantly stopped. As previously pointed out, however, the valve piston 82 is maintained pneumatically held or stuck in its: lower seated posiand thus ball valve ti remains eflective to prevent the further supply of fluid under pros Sl.6 from supply reservoir 56 to the brake cylinders ii under control of relay it except as hereafter to be described.

In its actuated position, the contact member 232 of the relay 2! engages the associated contact members 2321) and thereby connects the wire 235 to the wire 29?, thus establishing a holding circuit for maintaining the magnet winding 22'! of the relay 2? energized thereafter independently of relay 28. Thus, notwithstanding that the relay 2.8 returns to its normal position in response to the deenergization of the magnet winding 234, the consequent separation of the contact member 238 of relay 28 from its associated contact members 2381) does not effect deenergization of the magnet winding 22'! of the relay El. Furthermore, due to the separation of the contact member 232 of the relay 27 from its associated contact members 232a, the return of the contact member 238 of the relay 28 into engagement with its associated contact members 238a is not effective to reestablish the circuit for energizing the magnet winding 85 of the slip magnet valve and the magnet winding 23d of the relay 28.

It should thus be apparent that as long as the slipping wheel accelerates rotatively back toward car or train speed at a rate in excess of 7.7 miles per hour per second, that is, a rate suflicient to maintain the leaf spring M2 engagement with its contact member i651), the relay 2'! will be maintained in its actuated position and accordingly the magnet winding H9 of the reapplication magnet valve 24 will be correspondingly energized.

' As previously explained in the description of "the reapplication magnet valve 24, the energization of the magnet Winding H9 thereof instantly effects the unseating of the valve piston I I6, and fluid under pressure is accordingly resupplied to the brake cylinders H of truck No. 1 fromthe corresponding supply reservoir 25. Since the supply reservoir 25 is charged to main reservoir pressure and has adequate capacity for a maximum brake application, the reapplication of the brakes on the slipping wheel and the other wheels of the same truck is positively assured.

It should be noted that the ball valve 8i of the slip magnet valve 23 remains seated and thus continues to prevent the supply of fluid under pressure from the supply reservoir 56, under control of relay iii. The reason for preventing the supply of fluid under pressure to the brake cylinder under the control of relay i5 is that relay i5 does not have sufiicient capacity nor is it suthciently rapid to cause an adequate restoration or" pressure in the brake cylinder during the short interval of time that the slipping wheel exceeds a rate of 7.7 miles per hour per second. Thus reapplication magnet valve 24, which is of large capacity and which operates very rapidly, is provided for this purpose.

As long as the slipping car wheel accelerates back toward a speed corresponding to car or train speed at a rate in excess of that required to maintain the leaf spring H32 in contact with the contact finger lEEa, here assumed to be 7.7 miles ,2? which are thus promptly deenergized. The

valve piston H6 of the reapplication magnet valve 2% is thus instantly reseated to close off the further supply of fluid under pressure to the brake cylinders H from reservoir 25.

The choke, i3l in the pipe 9 3 controls the rate or" resupply of fluid under pressure to the brake cylinders l l suificiently, in relation to the rate of reduction of pressure effected through the exhaust port 98 of the slip magnet valve 23, that the pressure reestablished in the brake cylinder is less than the pressure originally established in vthebrake cylinders and which initiated the slip- Ping of the wheel.

The pressure reestablished in the brake cylinders l i of the wheel truck having a slipping wheel is also less than that which initiated the slipping of the wheel for the reason that the release valve piston 83 of the slip magnet valve 23 continues unseated and thus vents fluid under pressure from the brake cylinders from the time that a wheel begins to slip until it attains a rotative acceleration rate of 7.7 miles per hour per second, whereas the resupply of fluid under pressure to the brake cylinders ii is effected only during the lesser time interval that the slipping wheel accelerates rctatively at a rate in excess of 7.7 miles per hour per second. Accordingly, the pressure reestablished in the brake cylinders is appreciably lower than that which initiated the slipping of the wheel and, consequently, the likelihood that slipping of the wheels will again occur during the application of the brakes is minimized.

It will be apparent that with the deenergization of the magnet winding 22'! of the relay 27 in response to the decrease in the acceleration rate of the slipping wheel below 7.7 miles per hour tion coordinator 26 are all restored to the normal condition thereof in readiness for a subsequent operation thereof. I T

It will also be apparent that by so arranging the operation andinterrelation of the relays 21, 28 and 29 of the direction coordinator. 26 as to cause the magnet winding 85 of the slip magnet valve 23 to be energized continuously, .once a vehicle Wheel with which the slip magnet valve is associated begins toslip, untilthe slipping Wheel accelerates rotatively at a rate in excess of 7.7 milesper hour per second, the ultimate release of the brakes on a slipping wheel is positively assured. This is so because if, in spite of all the control equipment provided, a vehicle wheel should slip sufliciently as to actually attain a locked-wheel or sliding condition, the continued release of the fluid pressure from the brake cylinder will ultimately reduce the application of the brakes suiiiciently as to cause the sliding wheel to begin to accelerate and thus permit only momentarysliding of the wheel.

The distinguishing characteristic of my present invention over the equipment disclosed in my prior Patent 2,132,959 is that a positive acceleration of the slipping wheeel at a rate in excess of a certain rate is required to terminate the automatic venting of fluid under pressure from the brake cylinders associated with the truck having the slipping wheel. In my prior patent, the release of fluid under pressure from the brake cylinder or cylinders applying the brakes on a slipping Wheel is cut off whenever the slipping wheel begins to decelerate at a rate less than a certain rate, without requiring a positive acceleration of the slipping wheel at a rate in excess of a certain rate as in my present invention. It will accordingly be seen that my present invention provides protection against continued slidingof a car wheel not offered by the equipment disclosed in my prior patent.

(c). Duo-directional characteristic of brake control In the above description of the operation of my invention in connection with an assumed wheel-slipping operation, it was assumed that the car wheel Was rotating in a counterclockwise direction. Conceivably, the car might be so located and positioned in a train that thewheels of the trucks No. I and 2 rotate in a clockwise direction. In such case, it should be apparent that upon the deceleration of a slipping Wheel, the inertia ring I39 of the rotary inertia device 22 associated with the slipping wheel will shift in a clockwise direction, as seen in Fig. 1, for deceleration of the wheel and in a counterclockwise direction for acceleration of the wheel. Thus, instead of the leaf spring I42 contacting the contact members I651 and I65a, in the order named, it will contact the contact members I65ct and I651), in the order named, while the wheel is slipping. The relation and the'connection of the relays 21, 28 and 29 of the direction coordinator 29 is such, however, as to always cause the energization of the magnet winding 85 of the slip magnet valve 23 upon deceleration of the wheel and the energization of the magnet winding H9 of the reapplication of the magnet valve 24 upon acceleration of the slipping wheel. It will be apparent that such is the case because contact members I652) and I65a of the rotary inertia device. 22 are connected together electrically, the direction coordinator responding to the initial per second, the relays 21, 28 and 29 of the direcengagement of the leaf spring I 42with either of the contact fingers I651) to "55a to energize the magnet 85 of the slip magnet valve and responding upon the second engagement of the leaf spring I42 with either of the contact members I651) or I65a to'efieot deenergization of the magnet Winding 85 and energization of the magnet winding I I9. Accordingly, it makes no difference which way a car wheel I 9 is rotating, that is, in a counterclockwise direction or clockwise direction, when it begins to slip, the direction coordinators 26 functioning in any case sole- 1y on a basis of the closing of two switches in succession.

This arrangement of the rotary inertia devices and the direction coordinator is. such that three slip rings only are required for the six contact fingers associated with the leaf spring I42 of the rotary inertia devices instead of six as required in the arrangement shown in my prior Patent 2,132,959.

When the car or train comes to a complete Stop in response to the application of the brakes, the fact that the valve piston 82, of the slip magnet valve 23 associated with a Wheel truck on which a wheel slips during the application of the brakes, remains pneumatically held in its lower seated position causing the ball valve 8I to be seated, prevents the automatic resupply of fluid under pressure from supply reservoir I6 to the brake cylinders II of the corresponding truck. As previously pointed out the automatic return of the inertia ring I 39 of every rotary inertia device 22 to its normal position when the car or train is completely stopped interrupts the circuit for energizing the magnet winding 58 of the cut-01f magnet valve I9 on every car and, consequently,the pressure in the volume reservoir I8 is restored from the straight-air pipe I2 to that corresponding to the position of the brake valve handle 4| due to the unseating of the ball valve 45. Accordingly, it will be seen that if during the application of the brakes one or more of the wheels on a wheel truck slip, the seated ball valve M of the slip magnet valve 23 corresponding to that truck prevents the supply of fluid under pressure to the brake cylinders I! under the control of the corresponding relay I5 which is operated in response to that increase of pressure in the volume reservoir I8.

It should be seen that while the brakes may be released and reapplied on all the Wheels of a wheel truck, of which one wheel slips during the application of the brakes, the wheels of other wheel trucks on which no wheel slips during the application of the brake will be regulated in the normal manner by the rotary inertia devices 22 operating to regulate the rate of rotative retardation of the wheels to a substantially uniform rate.

((1). Release 0' the brakes When it is desired to release the brakes on all wheel trucks, including those on which a wheel may have slipped during the application of the brakes, it is necessary for the operator only to shift the brake valve handle 4| to its normal brake release position. When the pressure in the volume reservoirs I8 is reduced under the control of the brake valve I4, the relays l5 controlled thereby operate in a manner to release fluid under pressure from the brake cylinders II. one or more wheels of a given wheel truck have slipped during the application of the brakes, the ball valve 8| of the corresponding slip magnet valve 23 remains seated against the upward force of brake cylinder pressure effective in the chamber 93 on the ball valve 8|, until suiiicient reduction of pressure in chamber 86 has been effected by the relay IE to permit the ball valve to unseat. Accordingly, fluid under pressure does not begin to be released from the brake cylinders II on a truck having a wheel which slipped, until the pressure in the chamber 86 above the ball SE of the slip magnet valve associated with such truck reduces below brake cylinder pressure. When this occurs, the ball valve BI is unseated upwardly by the higher brake cylinder pressure and exhausted to atmosphere through the exhaust port of the relay I5.

The valve piston 82 of the slip magnet valve 23 associated with a truck on which a wheel slips during an application of. the brakes remains held seated on the annular gasket seat M38, as previously explained, notwithstanding the deenergization of the magnet winding 85 of the slip magnet valve. When the brake cylinder pressure in the chamber Q3 acting to maintain the valve piston #52 seated is reduced suiiiciently, the spring 9i again becomes effective to restore the valve piston 32 to its upper seated position on the annular rib seat 89 and the stem 68 .of the valve piston is accordingly shifted upwardly to again maintain the ball valve 81 unseated and reengage the contact member 98 with its associated contact members 98c, thereby reconditioning the slip magnet valve 23 for subsequent operation.

(e). Protection against undesired operation It is possible that, due to impact and shocks to the cars, as during switching operations, the rotary inertia devices 22 may be accidentally operated, that is, the inertia ring i353 of a rotary inertia device may be accidentally shifted out of its normal position sufficiently to effect engagement of the leaf. spring 542 with one or more of the contact fingers H3311, I63b, 54a, I641), l65a and i651).

If the brakes are released at the time of impact or shock, no harm is done because pressure switch 32 is open and prevents the supply of current of battery 3! under the control of the rotary inertia device. If the brakes are applied, however, at the time of impact or shock, the undesired engagement of leaf. spring with any of the contact fingers ifi ia, 3%, 165a and [6511 would result in the undesired operation of the release magnet valve it or the slip magnet valve 23 to release the brakes. Furthermore, since the piston valve 32 of the slip magnet valve 23 is pneumatically stuck in its lower position, once the slip magnet valve is operated, the brakes would be prevented from reapplying by the seated ball valve 8! without first releasing the brakes on the train.

In order to prevent such undesired operation, the choke or inductance coil 33 is provided in the supply from battery 3i. Choke 33 opposes the initial flow of current from battery 3 l in response to the engagement of a leaf spring I42 with any of. its associated contact fingers. Thus, unless a leaf spring Hi2 engages an associated contact finger longer than momentarily in an intended manner, insui'licient current will flow to pick up any of the various electromagnet windings controlled by the rotary inertia devices. Thus undesired and unintended operation of the brake control equipment will not occur.

SUMMARY Summarizing, it will be seen that I have provided a brake control equipment for a car or train including a rotary inertia device associated individually with each car wheel and a system of electrically controlled valves and relays effective in response to the operation of the rotary inertia devices to so regulate the application of the brakes on the wheels as to cause the car or train to decelerate at a substantially uniform rate. The rotary inertia devices associated with the car wheels are also adapted to cause a rapid release of the brakes on the wheels of, a truck having a slipping wheel or wheels and the automatic restoration of the application in response to the positive acceleration of the slipping wheel or wheels back toward a speed corresponding to car speed at a rate in excess of a certain rate. A distinguishing feature of my present invention as compared to my prior Patent 2,132,959 is that once a car wheel begins to slip, the automatic release of fluid under pressure from the brake cylinder applying the brakes on the slipping wheel is continued thereafter until the slipping wheel exceeds a certain positive acceleration rate at which time the automatic release of. fluid under pressure from the brake cylinders is cut off and resupply of fluid under pressure to the brake cylinders initiated. Thus in the event that a car wheel actually does slide, it can do so only momentarily since the release of the brakes continues to take place until the wheel positively accelerates at a rate in excess of a certain rate.

The brake control equipment is such as to control the brakes of a wheel truck having a slipping wheel individually and preventing the slipping Wheel from affecting the brakes on other wheel trucks having no slipping wheel so that the application of brakes on trucks having no slipping wheels is continued undiminished at the rate determined by the rotary inertia devices thereon. Accordingly protection against sliding of the Wheels is provided without materially lengthening the stopping distance because the application of the brakes is continued to an undiminished degree of. all wheel trucks having no slipping wheels.

A direction coordinator of novel construction is provided for automatically efiecting the operation of the brake control equipment during a wheel slip condition for either direction of the rotation of the car wheels, that is, whether a car is traveling in a forward or a backward direction. The direction coordinator so cooperates with the rotary inertia devices associated with the car wheels as to always cause first the release of the brakes upon deceleration of. the slipping wheel and then reapplication of the brakes upon acceleration of the slipping wheel. The rotary inertia devices are adapted to close switch devices whenever the rate of deceleration or acceleration of the slipping wheel exceeds a certain rate. These switch devices are connected in parallel and the direction coordinator is always responsive to the first switch closed to release the brakes and to the second switch closed to reapply the brakes.

The brake control equipment includes means for guarding against undesired operation of the brake control equipment in response to undesired operation of the rotary inertia devices caused by shocks to the cars. This means is illustrated in the form of an inductance coil in the circuits controlled by the rotary inertia devicesfor momentarily delaying the build-up of current in response to the accidental closure of switches by the rotary inertia devices. Since the switches of the rotary inertia devices are closed only momentarily if the operation thereof is accidental, the delay of current flow in the circuit controlled by the accidentally closed switches prevents the undesired operation of the brake control equipment.

The rotary inertia. devices are furthermore of novel construction in that a rotary inertia element is driven from a vehicle wheel through-a leaf spring which in turn forms a part of the electrical circuit controlled by the rotary inertia device. Thus, if theleaf spring forming a driving connection between the wheels and the rotary inertia element of the rotary inertia devices is broken, the electrical control of the rotary inertia device is destroyed and consequently no undesired operation due to the brakage of the spring connection can occur.

While I have shown and described a specific embodiment of my invention, it will be apparent that various omissions, additions or modifications may be made without departing from the spirit of my invention. It is accordingly not my intention to limit the scope of my invention except as it is necessitated by the scope of the prior art.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a brake system for a car or train, in

combination, meansfor effecting application and release of the brakes throughout the car or train, means operated automatically during an application of the brakes in response to the rotative deceleration of a car wheel at a rate in excess of a certain rate for initiating release of the brakes associated with the said wheel, and means operated automatically during an application of the brakes in response to the rotative acceleration of the said wheel at a rate in excess of a certain rate for terminating the release of the brakes associated with said wheel and effective to cause continued reapplication of the brakes associated with said wheel to an increasing degree only as long as the said wheel accelerates at a rate in excess of the second said certain rate.

2. In a fluid pressure brake equipment for a car or train, in combination, a brake cylinder eifective upon the supply of fluid under pressure thereto to effect application of the brakes associated with a car wheel and upon the venting of fluid pressure therefrom to effect the release of the brakes, manually controlled means for effecting the supply of fluid under pressure to and the venting of fluid under pressure from the brake cylinder, means operated automatically during an application of the brakes in response to the rotative deceleration of said wheel at a rate in excess of a certain rate for initiating the venting of fluid under pressure from the said brake cylinder, and means operated automatically during an application of the brakes in response to the rotative acceleration of the said wheel at a rate in excess of a certain rate for terminating the venting of fluid under pressure from the brake cylinder and effective to cause fluid under pressure tobe resupplied to the brake cylinder only as long as the said wheel rotatively accelerates at a rate in excess of the second said certain rate.

3. In a brake system for a car or train, manually controlled means for eifecting application and release of the brakes associated with the wheels of the car or train, means operated automaticallyl during an application of" the brakes in response to the rotative deceleration of a slipping wheel at a rate in excess of a certain rate for initiating the release of the brakes from the said wheel, and'means operatedautomatically in response to the rotative acceleration of the slipping wheel at a rate in excess of a certain rate to terminate the release of the brakes and cause continued reapplication of the brakes to an increasing degree only as long as the slipping wheel accelerates at a rate in excess of the second said certain rate.

4. In a fluid pressure brake system for a car or train, in combination, a brake cylinder effective upon the supply of fluid under pressure thereto to cause application of the brakes and upon the venting of fluid under pressure therefrom to cause release of the brakes associated with a car wheel, manually controlled means for causing fluid under pressure to be supplied to and released from the brake cylinder, means operated automatically during an application of the brakes in response to the rotative deceleration of the said car wheel at a rate in excess of a certain uniform rate while slipping for initiating the venting of fluid under pressure from the brake cylinder, and means operated automatically in response to the rotative acceleration of the slipping wheel back toward a speed corresponding to car speed at a rate in excess of a certain uniform rate for terminating the venting of fluid under pressure from the brake cylinder and effective to cause fluid under pressure to be resupplied to the brake cylinder only as long as the said car wheel accelerates at a rate in l excess of the second said uniform rate.

5. In a brake system for a car or train having the release of the brakes associated with said 1 wheel, and means operative in response to the shifting of said inertia element backwardly of its normal position to a certain degree for terminating the release of the brakes and effective to cause reapplication of the brakes associated with said wheel to an increasing degree only as long as the inertia element is displaced rotatively at least said certain degree backwardly of its normal position.

6. In a fluid pressure brake system for a car or train having a brake cylinder eifective upon the supply of fluid under pressure thereto to cause application of the brakes associated with a car wheel and upon the venting of fluid under pressure therefrom to cause the release of the brakes, the combination of rotary inertia means rotatable with said car wheel, said inertia means having a normal position with respect to said wheel and shiftable rotatively forward and backward from said normal position to different degrees according to the rate of rotative deceleration and acceleration respectively of said car wheel, means operative during an application of the brakes in response to the shifting of said inertia means forwardly of its normal position a certain degree for initiating the venting of fluid under pressure from the brake cylinder, and means operative during an application of the brakes in response to the shifting of said inertia element backwardly of its normal position a certain uniform degree for terminating the venting of fluid under pressure from the brake cylinder and for causing fluid under pressure to be resupplied to the brake cylinder to effect an increasingpressure therein as long as the inertia element is displaced rotatively at least said certain uniform degree backwardly of its normal position.

'7. In a brake system for a car or train having manually operated means for causing application and release of the brakes associated with all the car wheels, the combination of rotary inertia means rotatable with a car wheel, said inertia means having a normal position with respect to said wheel and shiftable rotatively at least a certain degree forwardly out of its said normal position in response to the rotative deceleration of the said wheel while slipping and shiftable rotatively backward at least a certain degree out of its normal position in response to the rotative acceleration of the said slipping wheel in returning back toward a speed corresponding to car speed, means operative during an application of the brakes in response to the shifting of said inertia element forwardly of its normal position at least said certain degree for initiating the release of the brakes associated with said wheel, and means operative during an application of the brakes in response to the shifting of said inertia element backwardly of its normal position at least said certain degree for terminating the release of the brakes associated with the slipping wheel and for causing reapplication of the brakes on the said wheel to an increasing degree as long the inertia element is displaced rotatively backward out of its normal position at least said certain degree.

8. In a fluid pressure brake system for a car or train having a brake cylinder effective upon the supply of fluid under pressure thereto to cause application of the brakes associated with a car wheel and upon the venting of fluid under pressure from said brake cylinder to effect the release of brakes from the said wheel and manually operative means for controlling the supply of fluid under pressure to and the release of fluid under pressure from the brake cylinder, the combination of rotary inertia means rotatable with said wheel, said inertia means having a normal position with respect to said wheel and shiftable rotatively forward out of its normal position at least a certain uniform degree in response to the rotative deceleration of the said wheel while slipping and shiftable rotatively backward out of its normal position at least a certain uniform degree in response to the rotative acceleration of the said wheel back toward a speed corresponding to car speed, means operative during an application of the brakes in response to the shifting of said inertia element forwardly out of its normal position at least said certain uniform degree for initiating the release of fluid under pressure from the brake cylinder, and means operative during an application of the brakes in response to the shifting of said inertia element backwardly out of its normal position at least said certain uniform degree for terminating the release of fluid under pressure from the brake cylinder and for causing the resupply of fluid under pressure to the brake cylinder to effect an increasing pressure therein only as long as the inertia element is displaced rotatively backward out of its normal position at least said certain uniform degree.

9. In a fluid pressure brake system for a car or train, the combination of a brake cylinder effective upon the supply of fluid under pressure thereto to cause application of the brakes associated with a car wheel and upon the venting of fluid under pressure therefrom to effect the release of the brakes, means providing a first com munication through which fluid under pressure be supplied to and released from the brake cylinder, manually controlled means for causing fluid under pressure to be supplied to the brake cylinder through said communication and. released from said brake cylinder through said communication, a supply valve in said communication normally permitting the supply of fluid under pressure through the communication to the brake cylinder and operative to a position to prevent the supply of fluid under pressure to the brake cylinder, a normally closed release valve in said communication between said valve and the brake cylinder effective when opened to release fluid under pressure from the brake cylinder, means operative in response to the rotative deceleration of the said wheel at a rate in excess of a certain rate for effecting operation of the said valve to prevent the further supply of fluid under pressure through the said communication to the brake cylinder and operation of the said release valve to release fluid under pressure from the brake cylinder, means providing a second communication separate from the first said communication through which fluid under pressure may be supplied to the brake cylinder, valve means controlling the supply of fluid under pressure through said second communication, and means operative in response to the rotative acceleration of the said wheel at a rate in excess of a certain rate for effecting operation of the said release valve to its normal closed position to cut off the release of fluid under pressure from the brake cylinder and to cause operation of said valve means to supply fluid under pressure to the brake cylinder through the second communication only as long as the said wheel accelerates rotatively at a rate in excess of a certain rate.

10. In a fluid pressure brake system for a car or train, the combination of a brake cylinder effective upon the supply of fluid under pressure thereto to cause application of the brakes associated with a car wheel and upon the venting of fluid under pressure therefrom to cause the release of the brakes, manually controlled means for causing fluid under pressure to be supplied to and released from the brake cylinder through said communication, rotary inertia means associated with said car wheel and operatively responsive according to the rate of deceleration and acceleration of the wheel, valve means controlled by the rotary inertia means and operative when the rate of rotative deceleration of the said wheel exceeds a certain rate for preventing the supply of fluid under pressure thereafter through said communication to the brake cylinder and for releasing fluid under pressure from said communication and the connected brake cylinder, said valve means being operative under the control of said rotary inertia means to terminate the release of fluid under pressure from the brake cylinder only after the said Wheel accelerates rotatively at a rate in excess of a cer- 

